/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.hotswap.agent.util.spring.io.loader;

import org.hotswap.agent.util.spring.io.resource.ContextResource;
import org.hotswap.agent.util.spring.io.resource.FileSystemResource;
import org.hotswap.agent.util.spring.io.resource.Resource;

/**
 * {@link ResourceLoader} implementation that resolves plain paths as file
 * system resources rather than as class path resources (the latter is
 * {@link DefaultResourceLoader}'s default strategy).
 *
 * <p>
 * <b>NOTE:</b> Plain paths will always be interpreted as relative to the
 * current VM working directory, even if they start with a slash. (This is
 * consistent with the semantics in a Servlet container.) <b>Use an explicit
 * "file:" prefix to enforce an absolute file path.</b>
 *
 * <p>
 * {@link org.springframework.context.support.FileSystemXmlApplicationContext}
 * is a full-fledged ApplicationContext implementation that provides the same
 * resource path resolution strategy.
 *
 * @author Juergen Hoeller
 * @since 1.1.3
 * @see DefaultResourceLoader
 * @see org.springframework.context.support.FileSystemXmlApplicationContext
 */
public class FileSystemResourceLoader extends DefaultResourceLoader {

    /**
     * Resolve resource paths as file system paths.
     * <p>
     * Note: Even if a given path starts with a slash, it will get interpreted
     * as relative to the current VM working directory.
     * 
     * @param path
     *            the path to the resource
     * @return the corresponding Resource handle
     * @see FileSystemResource
     * @see org.springframework.web.context.support.ServletContextResourceLoader#getResourceByPath
     */
    @Override
    protected Resource getResourceByPath(String path) {
        if (path != null && path.startsWith("/")) {
            path = path.substring(1);
        }
        return new FileSystemContextResource(path);
    }

    /**
     * FileSystemResource that explicitly expresses a context-relative path
     * through implementing the ContextResource interface.
     */
    private static class FileSystemContextResource extends FileSystemResource implements ContextResource {

        public FileSystemContextResource(String path) {
            super(path);
        }

        @Override
        public String getPathWithinContext() {
            return getPath();
        }
    }

}